Detection rules › Sigma

Potential BearLPE Exploitation

Status
test
Severity
high
Log source
category process_creation, product windows
Author
Olaf Hartong
Source
github.com/SigmaHQ/sigma

Detects potential exploitation of the BearLPE exploit using Task Scheduler ".job" import arbitrary DACL write\par

MITRE ATT&CK coverage

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

title: Potential BearLPE Exploitation
id: 931b6802-d6a6-4267-9ffa-526f57f22aaf
status: test
description: Detects potential exploitation of the BearLPE exploit using Task Scheduler ".job" import arbitrary DACL write\par
references:
    - https://github.com/djhohnstein/polarbearrepo/blob/f26d3e008093cc5c835e92a7165170baf6713d43/bearlpe/polarbear/polarbear/exploit.cpp
author: Olaf Hartong
date: 2019-05-22
modified: 2023-01-26
tags:
    - attack.persistence
    - attack.execution
    - attack.privilege-escalation
    - attack.t1053.005
    - car.2013-08-001
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\schtasks.exe'
        - OriginalFileName: 'schtasks.exe'
    selection_cli:
        CommandLine|contains|all:
            - '/change'
            - '/TN'
            - '/RU'
            - '/RP'
    condition: all of selection*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

all of selection*

Stage 1: selection_img

selection_img:
    - Image|endswith: '\schtasks.exe'
    - OriginalFileName: 'schtasks.exe'

Stage 2: selection_cli

selection_cli:
    CommandLine|contains|all:
        - '/change'
        - '/TN'
        - '/RU'
        - '/RP'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • /RP
  • /RU corpus 3 (sigma 3)
  • /TN corpus 2 (sigma 2)
  • /change corpus 3 (sigma 2, splunk 1)
field:"CommandLine" kind:match
Imageends_with
  • \schtasks.exe corpus 55 (sigma 55)
field:"Image" kind:ends_with value:"\schtasks.exe"
OriginalFileNameeq
  • schtasks.exe corpus 31 (sigma 18, elastic 9, splunk 4)
field:"OriginalFileName" kind:eq value:"schtasks.exe"